Feeding Friendsy: A Byte to Eat
(Published on 23. September 2026, 00:30 by Scojo)
RULES:
Fill the grid with the digits 1-9 so that digits don't repeat in a row, column or 3x3 box (marked with dotted lines).
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#FRIENDSHIPGOALS:
Scobot craves that zesty zip, that only vast quantities of stored electrons can provide! Help Scobot find a path through the maze to the battery so he can restore his energy reserves.
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MOVEMENT:
The path must not visit any cell more than once, cross itself or pass through any thick maze walls. As well as moving orthogonally, Scobot may move diagonally — if there's a 2x2 space in which to do so — but may never pass diagonally through the rounded end / corner of a wall.
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ONE-WAY DOORS:
Scobot may only pass directly through a purple arrow if moving in the direction the arrow is pointing. An arrow always points to the smaller of the two digits it sits between.
GEARS:
Digits separated by a gear have a 1:2 ratio (one is double the other). Not all possible gears have been given.
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TRIALS and TRAILS:
In this test of friendship, the path acts as a 'robot line', along which Scobot can move forwards and backwards. Scobot begins by inspecting the digit in his own cell. This tells him how many cells along his path he must move. The digit he stops on also gets inspected, and again tells him how many cells he must move. This time he can move in either direction, backwards or forwards, as long as there is enough room to move the correct distance (he may never overshoot the beginning or end of the path, and he can’t reverse direction mid-movement). He keeps repeating this process until he has inspected every cell along his path, without ever stopping at the same cell more than once. He will finish by stopping at the battery (the digit on the battery does not need to be inspected and so is of little importance.) For clarity, Scobot and the battery are the physical ends of the path, as well as being the first and last cells visited.
Furthermore, Scobot may never re-enter a box once he has left it, not even by reversing back along the path, so he must be thorough and finish all of his inspections in a box before moving on.
Good luck!
Solution code: Digits on Scobot's path in row 2, left to right
Comments
today, 00:18 by dr.Bunsen
Beautiful puzzle. It was my first puzzle with robot lines. I saw the advice to try other robot lines puzzles first, but decided to take the challenge. It was a while until I completed it and I enjoyed it alot.
The robot lines rules seem to be difficult at first sight, but in fact they are nice and not over complicated.
For me it is a great puzzle with 4 stars difficulty level. Thank you, Scojo
yesterday, 19:37 by KingGAEMING
Brilliant puzzle! It took me about 20 min using scrap paper to figure out how the Robot lines worked, but once I did that, the puzzle was fun! I thought I broke the puzzle in box 3, but the ending was fantastic! Great job Scojo!
yesterday, 09:18 by zeniko
After solving the original Robot Lines puzzle, this one turned out to be more approachable than expected, in particular since there were no loops. That narrow passage between r67c1 was cheeky, though, and the way that one box resolved brilliant. Thanks for sharing.
on 26. September 2026, 21:01 by Nairurian
This one really needs an example of how the robot line rule works.
on 26. September 2026, 18:33 by monsen
Lovely puzzle, really forced you to think about things. Found it quite hard, but doable.
on 25. September 2026, 18:38 by stranger
drawing robot lines looked rather daunting at first, although cross-box were the main source of weirdness in original series
4-star time for me
p.s. I have to ask how does one get plasma devoid of positive ions inside what looks like a chemical battery without immediately blowing it up
how does one even remove positive ions from plasma?
on 24. September 2026, 22:10 by Scojo
Clarified rules
on 24. September 2026, 16:31 by amirs
Brilliant construction! There was one box (you know which one...) that seemed absolutely impossible to fully inspect.
on 24. September 2026, 12:42 by AaronH
No wonder he needs more charge with all that back and forth he's doing.
Every time I thought I had finally gotten on top of this one, turns out I had actually confused myself again. However, it is a very interesting line type, well done for extending it to a path.
on 24. September 2026, 12:03 by Tortugo
I also found this much easier than others. I think I probably made some faulty deductions that turned out to be right.
on 24. September 2026, 09:53 by Fool on Hill
Nice puzzle. I think I must have worked out some key secrets of the line quite quickly, because I did not find it so hard as some.
on 23. September 2026, 23:54 by marty_sears
An amazing construction - very complex and full of big deductions and realisations. A fabulous use of the robot line ruleset, and makes me want to set with these again
on 23. September 2026, 20:25 by mscha
Robot Rally!
Oof, this was hard! I "cheated" by writing a little script to generate all possible (unique digit) robot lines, I couldn't have done it without it. That, plus some observations about the properties of (unique digit) robot lines helped, and I got this in 103 minutes.
Are we really getting 5 more that are even harder??
on 23. September 2026, 19:23 by LunchEntity
Definitely delivers that classic Marty-style "well, THIS is impossible ... oh wait but" experience. Nicely done!
on 23. September 2026, 18:35 by Laake
beep boop
on 23. September 2026, 14:05 by The Pi Guy
I don’t understand this ruleset at all! I’ve tried everything and there seems to be no way to not break the puzzle so I must be misunderstanding the rule somehow. There really needs to be an example showing how the rule works in context of the path.
on 23. September 2026, 14:05 by Christounet
Great puzzle and design! Even after solving "Robot Lines", it still took me some deep thinking to figure out all the properties of the ruleset. Definitely belongs to the 6 star territory for me. I wonder how harder the next puzzles might be if the difficulty increases for each entry. Thanks for this one :)
on 23. September 2026, 12:43 by Snookerfan
Very nice! There was a lot to learn about these lines. Thanks
on 23. September 2026, 06:54 by The Pi Guy
I don’t understand this ruleset at all! I’ve tried everything and there seems to be no way to not break the puzzle so I must be misunderstanding the rule somehow. There really needs to be an example showing how the rule works in context of the path.
on 23. September 2026, 05:38 by Thanos13
Another beautiful (and difficult) puzzle for this series! Loved it! Thank you, Scojo.
on 23. September 2026, 02:56 by Saltensity
Sorry for the silly question, but does re-entering a box include the robot reversing back into a box? Is he allowed to?
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He is not allowed to reverse back into a box, so he better be thorough and fully inspect all the path cells in that box before moving on :) - Scojo
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Thank you for your clarification, I successfully finished the puzzle! Half of the puzzle was understanding and figuring out the implications of the robot line, really took my brain for a ride. Thank you for this superb puzzle! ;D
- Saltensity
on 23. September 2026, 02:44 by ViKingPrime
01010011 01100011 01101111 01101010 01101111 00100000 01111001 01101111 01110101 00100000 01101000 01100001 01101110 01100100 01110011 01101111 01101101 01100101 00100000 01100100 01100101 01110110 01101001 01101100
on 23. September 2026, 01:56 by blackjackfitz
Huzzah!
on 23. September 2026, 01:49 by raaaaa
I love the robot line rule and would love to see it again. Today, it reappears in a series that I really like, and it's great! Thank you, Scojo. A great puzzle！
